1. Field of the Invention
The invention relates in general to a reading method of an optical disc drive, and more particularly to a reading method of an optical disc drive for reading a disc and finding if a disc is placed reversely.
2. Description of the Related Art
As the demand for high capacity memory storage medium increases, the use of discs plays an ever more important role. However, how to quickly, stably and correctly read data from the disc is still a focus of research and development to manufacturers.
In a conventional optical disc drive, the disc is placed on a spindle motor, then the spindle motor drives the disc to rotate. The disc has many tracks on which digital data is stored. The digital data is read by an optical pickup head disposed on a sled. After the sled is driven by a sled motor, the optical pickup head is moved to an appropriate position to read data from the disc.
However, the user may happen to place a disc into an optical disc drive incorrectly. For example, the disc is reversely placed in the optical disc drive. Meanwhile, the optical disc drive still continues to read data from the disc. As the disc is placed reversely, the optical disc drive can not read data from the disc successfully. After a number of error retries, the optical disc drive finds that data can not be read and ejects the disc from the optical disc drive accordingly. During the process of error retry, the optical disc drive continues to make annoying noise, which will not disappear until the disc is ejected from the optical disc drive. Particularly, if the optical disc drive is able to focus on the disc placed reversely, the optical disc drive takes longer time to come to the decision that data can not be read and the disc has to be ejected.